package com.zving.demo;

import java.awt.Color;  
import java.io.BufferedOutputStream;  
import java.io.File;  
import java.io.FileOutputStream;  
import com.lowagie.text.Element;   
import com.lowagie.text.pdf.BaseFont;  
import com.lowagie.text.pdf.PdfContentByte;  
import com.lowagie.text.pdf.PdfGState;  
 
import com.lowagie.text.pdf.PdfReader;  
import com.lowagie.text.pdf.PdfStamper; 
public class PdfWaterPrint {

    public static void main(String[] args) {
        try {
            // 目標pdf檔案  
            BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(new File("E:/BBB.pdf"))); 
            
 
// 源pdf檔案
            setWatermark(bos, "E:/AAA.pdf",16);  
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void setWatermark(BufferedOutputStream bos, String input, int permission){  
        try {
            PdfReader reader = new PdfReader(input);  
            PdfStamper stamper 
 
= new PdfStamper(reader, bos);  
            int total = reader.getNumberOfPages() + 1;  
            PdfContentByte content;  
            BaseFont base = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H",BaseFont.EMBEDDED);  
            PdfGState gs = new PdfGState();  
            for (int i = 1; i < total; i++) {  
                content = stamper.getOverContent(i);// 在內容上方加水印  
                gs.setFillOpacity(0.2f);  
                content.beginText();  
                content.setColorFill(Color.LIGHT_GRAY);  
                content.setFontAndSize(base, 50);  
                content.setTextMatrix(70, 200);  
                content.showTextAligned(Element.ALIGN_CENTER, "新聞記者證核發辦公室", 300,350, 55);  
                content.setColorFill(Color.BLACK);  
                content.setFontAndSize(base, 8);  
                content.showTextAligned(Element.ALIGN_CENTER,"", 300, 10, 0);  
                content.endText();  
      
            }  
            stamper.close();
        } catch (Exception e) {
            e.printStackTrace();
        }  
    } 
     

}

所需要得jar包